Randomized natural experiments provide social scientists with rare
opportunities to draw credible causal inferences in real world
settings. We capitalize on such a unique experiment to examine how
the name order of candidates on ballots affects election outcomes.
Since 1975 California has randomized the ballot order for statewide
offices with a complex alphabet lottery. Adapting statistical
techniques to this lottery and addressing methodological problems of
conventional approaches, our analysis of statewide elections from
1978 to 2002 reveals that in general elections ballot order
significantly impacts only minor party candidates, with no
detectable effects on major party candidates. These results
contradict previous research finding large
effects in general elections for major party candidates. In
primaries, however, we show that being listed first benefits
everyone. Major party candidates generally gain one to three
percentage points, while minor party candidates may double their
vote shares. In all elections, the largest effects are for
nonpartisan races, where candidates in first position gain three
percentage points.